This invention relates generally to stabilizer pads for vehicles, and more particularly to improved stabilizer pad configurations which can be used in conjunction with a pivotally mounted, two-way stabilizer pads.
Construction equipment, such as earth-moving vehicles and the like, must be stabilized during construction or digging operations to prevent movement of the equipment or vehicles. Typically, stabilization is provided by hydraulically actuated arms that extend from the vehicle and that have earth-engaging pads mounted on their distal ends. When the vehicle or equipment is moved into a working position, if extra stability is needed, the stabilizer arms are hydraulically operated to move from a retracted position, in which the arms generally extend upwardly and out of the way, to a user position in which the arms extend downwardly at an acute angle to the ground surface so that the pads contact the ground surface. When it is desired to move the vehicle, the arms are returned to the retracted position, and the vehicle is moved to a new operating location.
Reversible stabilizer pads for construction equipment, such as earth-moving vehicles and the like, are well-known in the prior art. Examples of such pads are found in U.S. Pat. Nos. 4,761,021 and 4,889,362. Such stabilizer pads generally have a first surface for engagement with a softer surface, such as gravel and soft earth, and a more resilient second surface on the opposite side of the first surface for engagement with harder surfaces, such as concrete or asphalt. Typically, the first surface includes flanges with grouser points that permit the pads to dig into the softer, unfinished surface formed by gravel or soft earth, to better anchor and stabilize the vehicle when encountering difficult digging conditions. The first surface is unsuitable for contact with a hard surface, since the grouser points could damage or mar the hard asphalt or concrete. The second surface of the pad typically is formed of a laminated, rubber pad for better stability on the more solid surface provided by concrete or asphalt. The stabilizer pad typically is pivotally mounted to the distal end of the hydraulically operated arm so that the pad may be rotated to contact the ground with either the first surface or the second surface.
While such prior art laminated structures are suitable for engagement with concrete or asphalt, the construction of such pads is expensive, labor-intensive and time consuming. It is desirable to provide suitable laminated pad assemblies for use on the resilient, second surface of the stabilizer pad that can be fabricated in an automated manner, and that provide improved stability and longer wear.
To achieve the foregoing desired objectives, in accordance with the present improved invention, there are provided resilient, laminated stabilizer pad assemblies for stabilizer pads for use on the side of the pad opposite the grouser points for engagement with hard asphalt or concrete surfaces. The improved pad assemblies of the present invention are preferably for use in conjunction with reversible stabilizer pads, but may also find use in connection with other pad applications.
In accordance with one aspect of the present invention, the resilient stabilizer pad assemblies include a bracket which typically is formed from a piece of metal and which is bent or otherwise deformed to partially surround and capture the resilient portion of the pad assembly. The resilient portion of the pad assembly typically is a laminate formed of a plurality of parallel layers of rubber or other like materials. The laminate is attached to the bracket by a connector or pin which passes through each of the layers of the laminate. Extending from an upper surface of the bracket are a plurality of mounting devices, such as studs or bolts which are adapted to pass through a plate on the stabilizer pad to permit the attachment and removal of the pad assemblies as needed.
In another aspect of the invention, each of the brackets is formed of a planar piece of material such as steel which is bent during the forming process. In one embodiment flaps are formed which capture the laminate between them and hold the layers together. To prevent the upper flat surface of the bracket from bowing during the forming process, a force must be applied downwardly toward the laminate. In another aspect of the present invention, a reverse bend or camber is applied to the upper flat surface of the bracket to offset the bowing tendency of the bracket. In another embodiment, reinforcing ribs are provided to prevent bowing of the bracket.
In another embodiment, bowing of the bracket may be minimized and bending of the flaps may be facilitated by the removal of material along the fold lines, such as by forming score lines or holes or the like along the fold lines.
In another aspect of the invention, various techniques may be utilized to secure and restrain the laminated layers, including a nut and bolt, welded pins, or a pin welded at one end and threaded at the other for attachment of a nut.
In yet another aspect of the present invention, inaccuracies or lack of standardization of the thicknesses of the layers. of the laminate can be accommodated by the provision of a compressible layer of material disposed amongst the layers of the laminate that may be compressed to the desired size by applying lateral forces to the laminate.
In yet another aspect of the invention, the laminate may be affixed to the bracket by lips extending from flaps on the bracket into notches or channels formed in the laminate.
In yet another aspect of the invention, the laminate may include multiple projections and is affixed to a metal frame which includes strips residing in valleys disposed between the projections formed in the laminate.
In yet another further aspect of the invention, the layers of the laminate may not be of all the same height. Rather, they may be stepped in such a manner that the layers adjacent the flaps of the bracket have the smallest height, while the layers in the center of the pad farthest from the flaps have the greatest height. This arrangement prevents splaying of layers of the laminate closest to the flaps of the bracket.
Other embodiments of this invention relate to the methods for assembling the pad assemblies described above.
The foregoing pad assemblies made in accordance with the present invention can be constructed more quickly and cheaply than prior art pad assemblies which required multiple, manual steps. Such pad assemblies provide superior performance and may be attached to and removed from existing stabilizer pads in the same manner as prior art pad assemblies. Finally, particularly with respect to some of the embodiments described above, the structures permit a greater thickness of resilient material below the lower edge of the bracket, thus providing a longer life to the pad.